Left-sided positive vocal sounds preferred by the brain.

The brain's primary auditory cortex is more responsive to positive human vocalizations coming from the left side than to any other kind of sounds. This bias can be explained by the way our brain is organized, but its evolutionary significance is not yet known. The preference of the primary auditory cortex for positive human vocalizations from the left is still unclear, and it is unknown whether this is a uniquely human characteristic.